feat: gather process tree information

[addaleax]

Add a --show-process-tree that shows a pretty tree of all spawned processes after nyc has run.

The data files for that are stored in processinfo are stored in (temp directory)/processinfo so that they don’t interfere with the fixed format of the coverage files.

Fixes: #158

Right now this only displays the commands as they are being run, ex:

$ nyc --show-process-tree npm run pretest

> nyc@8.1.0 pretest /home/sqrt/src/nyc
> standard

----------|----------|----------|----------|----------|----------------|
File      |  % Stmts | % Branch |  % Funcs |  % Lines |Uncovered Lines |
----------|----------|----------|----------|----------|----------------|
All files |  Unknown |  Unknown |  Unknown |  Unknown |                |
----------|----------|----------|----------|----------|----------------|
nyc
└─┬ /usr/local/bin/node /usr/local/bin/npm run pretest
  └── /usr/local/bin/node /home/xxxx/src/nyc/node_modules/.bin/standard

Note: Unlike described in the above issue, I’ve opted to leave environment variables out of the stored data because they may contain sensitive information and there have been cases of .nyc_output accidentally being published.

Any thoughts?

[bcoe]

@addaleax I like this as a start to addressing #158! It looks like the tests are failing because Travis is outputting the hierarchy in a different ordering than your local machine, it outputs branch 4 and then branch 3 -- adding a sorting step might be a good fix for this?

A couple thoughts:

• I think It would be worth pulling the process-tree logic into its own module lib/process.js?, since the
  logic isn't too coupled with the rest of the logic in index.js.
  • this might mean tweaking our coverage logic a bit, to instrument an additional file.
• I think one thing @isaacs was picturing, was, could we get the coverage percentage for a given branch?
  • this could be a cool eventual addition to functionality, and is another argument for starting to isolate the branching logic into its own module.

[addaleax]

adding a sorting step might be a good fix for this?

Done! I definitely should have thought of that… 😄

I think It would be worth pulling the process-tree logic into its own module lib/process.js?

Sounds like a good idea… I’ve started splitting things up, I guess I’ll see if I get the self-coverage handling right.

could we get the coverage percentage for a given branch?

Definitely, and I agree that that would a pretty neat thing to have! It might require touching a bit more of the reporting logic, though.

[bcoe]

could we make it so we only create this directory, if we've enabled process tracking; my thinking is, let's make the behavior 100% identical, unless you are outputting the process tree.

[addaleax]

hmm, I’ll try that

[bcoe]

Definitely, and I agree that that would a pretty neat thing to have! It might require touching a bit more of the reporting logic, though.

Let's hold off on this until V2 💃

I made a few more comments, also we should definitely figure out a good place to document this in the README; this having been said, I'm really loving this feature.

[addaleax]

Let's hold off on this until V2

You mean, this PR, or per-subtree coverage reporting? I’m fine with either, but if you’re talking about the latter, I’d want to try and implement per-subtree reporting to make sure everything’s wired up in order for that to work

(edit: … i took the liberty to throw away all old coveralls comments which were clobbering up everything here)

[coveralls]

Changes Unknown when pulling 88021d0 on addaleax:process-tree into * on istanbuljs:master*.

[bcoe]

You mean, this PR, or per-subtree coverage reporting?

@addaleax I think this pull request is great, and we should land it ASAP -- just want to get the behavior identical if it's not enabled, and add some documentation to the README 👍

[addaleax]

just want to get the behavior identical if it's not enabled

I think that’s the case. :)

and add some documentation to the README

Done! Please make sure this PR is in the state you’d like it to see in :)

[coveralls]

Changes Unknown when pulling 3dad767 on addaleax:process-tree into * on istanbuljs:master*.

[bcoe]

@addaleax awesome, on a short vacation to NYC, but will hopefully land some pull requests tomorrow or Monday.

[isaacs]

on a short vacation to NYC, but will hopefully land some pull requests tomorrow or Monday.

That's right, @bcoe is so committed to Open Source, he takes vacations just to visit his node modules.

[addaleax]

@isaacs … glad to hear your dad joke license arrived ;) (ok truth is i have been giggling at this for five minutes straight)

[bcoe]

@isaacs is this what you were picturing with #158, seems like a great start.

[isaacs]

@bcoe @addaleax Yeah, this looks really cool. It strikes me now that maybe storing the environment variables is a bad idea, since people will occasionally publish a coverage or .nyc_output folder to npm or github, and environs often have passwords in them.

[bcoe]

@addaleax mind giving the next release a spin:

npm cache clear; npm i nyc@next

if QA is looking good, we'll get this promoted soon.

[addaleax]

@bcoe Everything looks good so far :)